The Celtics came back from a 26-point deficit in the fourth quarter — cutting the margin to 4 — but could not catch the Knicks in Game 6 Friday night. Overrated ball hog Carmelo Anthony scored 7 straight points, snapped a string of 19 consecutive 3-point misses, and led the Knicks to an 88-80 victory over the gritty, graying Celtics.

And now we wonder, what happens to the Celtics we grew to know and love?

Will Doc Rivers leave? Will the Celtics trade Paul Pierce or buy him out of his contract? Will Kevin Garnett retire after 18 seasons?

No one knows anything. And there was a ton of ambiguity in the Celtics dressing room after the game. Rivers would not commit to another season. Pierce didn’t want to answer a question about himself and Garnett “having the talent” to make another run. Garnett sounded like he might not want to be back if Pierce is not back with the Celtics.

“I’m sure there’s going to be a lot of changes here,’’ said Pierce. “It’s up to Danny [Ainge]. I definitely expect to be playing next year.’’

“All three of us agreed to speak about it later,’’ said Garnett. “I think we need some additions. Health hit us pretty hard this year. One of the big reasons I came here was because of Paul . . . We haven’t had that conversation. When it’s time, I’m sure we’ll be able to find you.’’

The official end of the New Big Three Era (it became Big Two when Ray Allen left) came at 9:55 p.m. Friday when the Knicks staggered off the parquet with their first playoff series victory in 13 years. They will go on to play the Indiana Pacers in Round 2, and their delusional, desperate fans actually think they have a chance to knock off the Miami Heat in the conference finals. They have no chance, of course. They are mentally weak. But that is their problem.

Our problems are right in front of our eyes. The Celtics are in trouble. They are crumbling. They need to start over. We’ve said this before, of course, and we’ve been wrong because Pierce and KG and Doc kept coming back.

Typically, Pierce’s final moment Friday was without ceremony. He was replaced by Terrence Williams with 27.3 seconds left and the Celtics trailing by 8.

“I don’t think the fans knew at that point,’’ said Rivers. “He still could have gone back into the game. He’s one of the greatest Celtics to ever play. We live in a day and time where guys are changing teams like socks. And Paul has chosen to stay throughout his career, when clearly he has all rights to leave and he chose to stay here. When I first got here we were really rebuilding. He never wavered. I give him an amazing amount of respect. He wanted to get it done here and he made that choice. I hope he’s remembered for that. I hope he comes back. I just don’t know anything.’’

Garnett came off the floor with 18.1 seconds left. Fans noticed. Garnett hugged Rivers, Pierce, and the rest of his teammates.

“I couldn’t be more proud of this group,’’ said Rivers. “Kevin limped into the playoffs. Toughest competitor I’ve ever been around. I really didn’t want him to go out that way on our court. He’s the best that I’ve seen.’’

Clearly, it is time to break up the old gang that brought one championship and multiple playoff wins since the start of the 2007-08 season. The Celtics have become the local team with the least amount of hope. Would anyone dispute the notion that the Patriots, Bruins, and Red Sox (yes, even them) are closer to a championship than the Celtics?

It’s time to trade proud Pierce (4 for 18 from the floor Friday night) or maybe Rajon Rondo (was he really in Vegas?) or perhaps Jeff Green (his value is high). Time to go with Hank Finkel for a year and get worse in order to get better. The Celtics’ last legitimate championship hope was dissolved when Ainge dealt Kendrick Perkins in the winter of 2011. The Celtics have been a patchwork project since that deal, getting older and worse.

We had our little fun at the expense of Melo and the Knicks over the last couple of days. Thousands of New England college students got to tease their New York classmates. The Knicks looked silly in their Johnny Cash black Wednesday, and we delighted in reminding them how much this reminded us of the 2004 ALCS, when the Red Sox came back from 3-0 against the Yankees. There was one last moment of delight when it looked like the Knicks might choke again as the Celtics ran at them down the stretch.

But the 2004 Red Sox had talent and depth and the Celtics are lacking in both.

What about you, Doc? Are you coming back?

“I don’t know,’’ Rivers said. “Danny has already worked on stuff. He knows to give me about a week. We’ll figure it all out and we’ll see. We need more. We do. The key is for us — do you want to take away to get more? That decision will be made later.

“I don’t know. I can’t make that decision right now. We’ll see. Honestly, I just don’t know . . . I need to just detox and then we’ll find out.’’

Something has to change. The Celtics are shallow and offensively challenged. In this series, they had three halves in which they scored fewer than 30 points (27 in the first half Friday night).